Reverberation Adjusting Apparatus, Reverberation Correcting Method, And Sound Reproducing System

ABSTRACT

The present invention provides a sound reproducing system capable of accurately analyzing a reverberation characteristic of amplified sound including an arrival direction of a reverberation component, which is more natural, and has higher realistic sensation. A surround system  100  has a speaker system  130 , a signal processing apparatus  120  for recognizing a reverberation characteristic of a listening room  10  and adjusting a reverberation component of sound source to be amplified on the basis of the recognized reverberation characteristic, and a microphone array  140  constructed by a plurality of microphones M disposed in the listening room  10  and having the same characteristics, and in which distances among the microphones M are determined in advance. In the case where sound source is amplified and output from the speaker system  130  to the listening room  10 , the microphone array  140  collects amplified sound in a specific listening position in the listening room  10.

TECHNICAL FIELD

The present invention belongs to a technical field of a reverberationadjusting apparatus and a sound reproducing system capable of correctingreverberation.

BACKGROUND ART

In recent years, at the time of reproducing sound source such as music,a reproducing apparatus such as an AV amplifier that performs correctionof a sound field in a sound field space in which the sound source isreproduced is practically used. Recently, attention is being paid to atechnique of correcting a reverberation characteristic of sound sourceon the basis of the characteristics of a sound field space in whichsound source is reproduced and performing a reverberation control on thesound field space. In this case, it is important to accurately analyze areverberation characteristic in a sound field space in which the soundsource is reproduced, that is, a reverberation characteristic related tothe intensity of sound in a listening position of amplified sound. Inparticular, as a technique for analyzing such a reverberationcharacteristic, a method of analyzing a reverberation characteristic ofa sound field space by collecting a test signal amplified in the soundfield space into the sound field space is known.

Hitherto, a sound reproducing system for conducting such an analysis ofa sound field space has a plurality of speakers disposed in the soundfield space and a microphone disposed in a listening position in thesound field space and, when a predetermined test signal is amplified,for collecting amplified sound of the test signal. On the basis of thetest signal collected by the microphone, a characteristic of theamplified sound in the listening position is analyzed. On the basis ofthe analysis result, a signal process of sound source to be reproducedis performed (for example, Japanese Patent Application Laid-Open (JP-A)No. 2003-255955).

DISCLOSURE OF INVENTION Problems to be Solved by the Invention

However, in the conventional sound reproducing system, test signalsamplified and output from a plurality of speakers or a selected speakerare collected by a single microphone. Consequently, a reverberationcharacteristic having a direction characteristic indicative of anarrival direction of a reverberation component in amplified sound in alistening position, which is in the listening position of the amplifiedsound, cannot be estimated. The reverberation characteristic of thesound field space cannot be accurately analyzed, that is, thereverberation characteristic of the sound field space cannot beaccurately grasped. As a result, in the sound reproducing system, evenif the signal process of sound source to be reproduced is performed onthe basis of the analysis result, there is a case that the listenerfeels strange or sound source is reproduced without realistic sensationwhen the sound source is reproduced in the sound field space.

The present invention has been achieved in consideration of theproblems. An object of the invention is to provide a sound reproducingsystem and a reverberation adjusting apparatus capable of accuratelyanalyzing a reverberation characteristic in a listening position ofamplified sound, which has a direction characteristic of a reverberationcomponent of the amplified sound in the listening position, andreproducing sound more naturally and with higher realistic sensation onthe basis of the analyzed reverberation characteristic.

Means for Solving the Problems

To solve that problem, a first aspect of the invention provides a soundreproducing system comprising: a speaker system constructed by aplurality of speakers disposed in a sound field space; a reverberationadjusting apparatus for recognizing a reverberation characteristic inthe sound field space by amplifying sound source by the speaker systemand, on the basis of the recognized reverberation characteristic,adjusting a reverberation component in the sound source which is outputfrom the speaker system; and a microphone array which is constructed bya plurality of microphones disposed in the sound field space and havingthe same characteristics, in which distances among the microphones arepreliminarily determined and, when the sound source is amplified and theamplified sound is output from the speaker system to the sound fieldspace, for collecting the amplified sound in a specific listeningposition in the sound field space, wherein the reverberation adjustingapparatus comprises: a first obtaining device for obtaining a soundsignal as the sound source; a generating device for generating, as thesound source, a test signal used for analyzing a reverberationcharacteristic of the sound field space; an output control device foramplifying at least one of the sound signal and the test signal andoutputting the amplified signal from the speaker system; a secondobtaining device for obtaining, as an amplified sound signal, anamplified sound collected by the microphone array; a recognizing devicefor recognizing a reverberation characteristic having a directioncharacteristic indicative of an arrival direction of a reverberationcomponent of amplified sound in the listening position on the basis ofthe obtained amplified sound signal, and indicative of attenuation withtime in the sound field space on intensity of sound in the listeningposition of the amplified sound; and an adjusting device for adjustingthe reverberation characteristic of the sound source to be amplified andoutput from the obtained speaker on the basis of the recognizedreverberation characteristic.

According to a seventh aspect of the invention, there is provided areverberation adjusting method for adjusting a reverberation componentin sound source output from a speaker system constructed by a pluralityof speakers on the basis of a reverberation characteristic of a soundfield space to which amplified sound is output from the speaker system,comprising: a test signal amplifying process for generating a testsignal used for analyzing the reverberation characteristic in the soundfield space as the sound source, and amplifying the generated testsignal by the speaker system; a sound collecting process for collecting,as an amplified sound signal, the test signal output from the speakersystem to the sound field space by a microphone array which isconstructed by a plurality of microphones disposed in the sound fieldspace and having the same characteristics; a recognizing process forrecognizing a reverberation characteristic having a directioncharacteristic indicative of an arrival direction of a reverberationcomponent of amplified sound in the listening position on the basis ofthe obtained amplified sound signal, and indicative of attenuation withtime in the sound field space on intensity of sound in the listeningposition of the amplified sound; and an adjusting process, at the timeof obtaining and amplifying sound source to be amplified by the speakersystem, for adjusting the reverberation characteristic of the obtainedsound signal on the basis of the recognized reverberationcharacteristic.

According to an eighth aspect of the invention, there is provided areverberation adjusting apparatus for adjusting a reverberationcomponent in sound source output from a speaker system constructed by aplurality of speakers on the basis of a reverberation characteristic ofa sound field space to which amplified sound is output from the speakersystem, comprising: a first obtaining device for obtaining a soundsignal as the sound source in the case of collecting the sound amplifiedand output to the sound field space by the speaker system in a specificlistening position by a microphone array constructed by a plurality ofmicrophones disposed in the sound field space and having the samecharacteristics; a generating device for generating, as the soundsource, a test signal used for analyzing a reverberation characteristicof the source field space; an output control device for amplifying oneof the sound signal and the test signal and outputting the amplifiedsignal from the speaker system; a second obtaining device for obtainingan amplified sound signal collected by the microphone array; arecognizing device for recognizing a reverberation characteristic havinga direction characteristic indicative of an arrival direction of areverberation component of amplified sound in the listening position onthe basis of the obtained amplified sound signal, and indicative ofattenuation with time in the sound field space on intensity of sound inthe listening position of the amplified sound; and an adjusting devicefor adjusting the reverberation characteristic of the obtained soundsource to be output to the speaker system on the basis of the recognizedreverberation characteristic.

According to a ninth aspect of the invention, there is provided a soundreproducing system comprising: a speaker system constructed by aplurality of speakers disposed in a sound field space; a reverberationadjusting apparatus for recognizing a reverberation characteristic inthe sound field space by amplifying sound source by the speaker systemand, on the basis of the recognized reverberation characteristic,adjusting a reverberation component in the sound source which is outputfrom the speaker system; and a microphone disposed in the sound fieldspace, having a direction characteristic in a predetermined direction,when the sound source is amplified and the amplified sound is outputfrom the speaker system to the sound field space, for collecting theamplified sound in a specific listening position in the sound fieldspace, wherein the reverberation adjusting apparatus comprises: a firstobtaining device for obtaining a sound signal as the sound source; agenerating device for generating, as the sound source, a test signalused for analyzing a reverberation characteristic of the sound fieldspace; an output control device for amplifying at least one of the soundsignal and the test signal and outputting the amplified signal from thespeaker system; a second obtaining device for obtaining, as an amplifiedsound signal, an amplified sound collected by the microphone array; arecognizing device for recognizing a reverberation characteristic havinga direction characteristic indicative of an arrival direction of areverberation component of amplified sound in the listening position onthe basis of the obtained amplified sound signal, and indicative ofattenuation with time in the sound field space on intensity of sound inthe listening position of the amplified sound; and an adjusting devicefor adjusting the reverberation characteristic of the sound source to beamplified and output from the obtained speaker on the basis of therecognized reverberation characteristic.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram showing the configuration of a surround systemof an embodiment of the invention;

FIG. 2 is a diagram showing an example of the configuration of amicrophone array in the embodiment, which is a linear array;

FIG. 3 is a diagram showing an example of the configuration of amicrophone array in the embodiment, which is a cross array;

FIG. 4 is a diagram showing an example of the configuration of amicrophone array in the embodiment, which is a square array;

FIG. 5 is a diagram showing an example of the configuration of amicrophone array in the embodiment, which is a circular array;

FIG. 6 is a diagram showing an example of the configuration of amicrophone array in the embodiment, which is a radial array (I);

FIG. 7 is a diagram showing an example of the configuration of amicrophone array in the embodiment, which is a radial array (II);

FIG. 8 is a block diagram showing the configuration of a signalprocessor in the embodiment;

FIG. 9 is a block diagram showing the configuration of a spatialcharacteristic analyzer in the embodiment;

FIG. 10 is a diagram illustrating reverberation component arrivaldirection estimation in a reverberation characteristic analyzer in theembodiment;

FIG. 11 is a block diagram showing the configuration of reverberationcontrol circuit of the signal processor in the embodiment; and

FIG. 12 is a flowchart showing operations of process for setting areverberation control coefficient in a system controller in theembodiment.

DESCRIPTION OF REFERENCE NUMERALS

-   100 Surround system-   120 Signal processing apparatus-   130 Speaker system-   140 Microphone array-   127 Spatial characteristic analyzer-   127C Reverberant characteristic analyzer-   129 System controller-   200 Signal processor-   250 Reverberation control circuit-   251 Signal dividing unit-   252 Signal component generating unit-   253 Signal component combining unit

BEST MODE FOR CARRYING OUT THE INVENTION

Preferred embodiments of the invention will now be described based onthe drawings.

The embodiments described below relate to the case of applying areverberation adjusting apparatus or a sound field reproducing system ofthe invention to a 5.1ch surround system (hereinafter, simply referredto as surround system).

First, the configuration of the surround system of the embodiment willbe described with reference to FIG. 1. FIG. 1 is a block diagram showingthe configuration of the surround system of the embodiment. FIGS. 2 to 7are diagrams showing examples of the configuration of a microphone arrayof the embodiment.

As shown in FIG. 1, a surround system 100 of the embodiment is disposedin a listening room 10, that is, a sound field space for providing thelistener with reproduction sound. The surround system 100 reproduces orobtains a sound source and performs a predetermined signal process onthe reproduced sound or obtained sound. The surround system 100amplifies the signal-processed sound on the speaker unit basis by a5.1ch speaker system 130, thereby providing the listener with a soundfield space with the presence of a live performance (with surroundingsound).

The surround system 100 is constructed by: a sound source outputapparatus 110 for outputting bit stream data of a predetermined formathaving a channel component corresponding to each speaker by reproducinga sound source such as a recording medium or obtaining a sound sourcefrom the outside such as a television signal; a signal processingapparatus 120 for decoding the bit stream output from the sound sourceoutput apparatus 110 to an audio signal for each channel, performing asignal process on the audio signal of each channel, and analyzing areverberation characteristic and the other spatial characteristics ofthe listening room 10; the speaker system 130 consisted of variousspeakers corresponding to various channels; and a microphone array 140used at the time of analyzing the spatial characteristics of thelistening room 10.

The channels denote transmission paths of the audio signals output tothe speakers, and each channel transmits an audio signal basicallydifferent from audio signals of the other channels.

For example, the signal processing apparatus 120 of the embodimentcorresponds to a reverberation adjusting apparatus of the presentinvention, the speaker system 130 corresponds to a speaker system 130 ofthe invention, and the microphone array 140 corresponds to themicrophone array 140 of the invention.

The sound source output apparatus 110 is constructed by, for example, anapparatus for reproducing media such as CD (Compact Disc) or DVD(Digital Versatile Disc) or a receiving apparatus for receiving adigital television broadcasting. The sound source output apparatus 110reproduces a sound source such as CD or obtains a broadcasted soundsource and outputs bit stream data having a channel componentcorresponding to 5.1ch to the signal processing apparatus 120.

To the signal processing apparatus 120, the bit stream data havingchannel components output from the sound source output apparatus 110 isinput. The signal processing apparatus 120 decodes the input bit streamdata to audio signals of the respective channels.

The signal processing apparatus 120 performs:

(1) adjustment of the frequency characteristic of each of the decodedaudio signals;

(2) addition of a preset reverberation component to each of the decodedaudio signals;

(3) adjustment of the signal level and a delay amount in each of thedecoded audio signals; and

(4) analysis of the spatial characteristics such as the frequencycharacteristic and the reverberation characteristic in a listeningposition in the listening room 10, and conversion of the audio signalssubjected to the signal process to analog signals, thereby adjusting thesound volume level. The signal processing apparatus 120 outputs theaudio signals whose sound volume level has been adjusted to the speakersof the speaker system 130.

The details of the configuration and operation of the signal processingapparatus 120 in the embodiment will be described later.

The speaker system 130 has: a center speaker 131 disposed in front of alistener; a front right speaker (hereinafter, referred to as FR speaker)132FR and a front left speaker (hereinafter, referred to as FL speaker)132FL disposed in front of the listener and on the right or left side ofthe center speaker 131; a right surround speaker (hereinafter, referredto as SR speaker) 133SR and a left surround speaker (hereinafter,referred to as SL speaker) 133SL disposed on the rear side of thelistener and on the right or left sides, respectively, of the FR speaker132FR and the FL speaker 132FL; and a low-frequency reproduction speaker(hereinafter, referred to as sub woofer) 134 disposed in an arbitraryposition.

Specifically, the center speaker 131, the FL speaker 132FL, the FRspeaker 132FR, the SL speaker 133SL, and the SR speaker 133SR arefull-range speakers having the reproducible frequency characteristic inalmost the full range of the frequency band used at the time ofamplifying an audio signal. Each of the speakers amplifies the audiosignals with its radial axis directed to the listening position. The subwoofer 134 is used at the time of amplifying signals in a predeterminedlow frequency band.

The microphone array 140 is constructed by a plurality of microphones Mdisposed in the listening room 10 and having the same characteristic.When an audio signal is amplified and output from the speaker system 130to the listening room 10, the microphone array 140 collects theamplified sound in a specific listening position in the listening room10. In particular, in the microphone array 140 of the embodiment, theamplified sound based on the test signal output from the speaker system130 is collected on the microphone M unit basis. The microphone array140 converts the collected amplified sound to an electric signal, andoutputs the electric signal as a collected sound signal (hereinafter,also referred to as amplified sound signal) to the signal processingapparatus 120.

Specifically, the microphone array 140 has a configuration in which theplurality of microphones M are arranged on a plane parallel with thefloor surface of the listening room 10.

For example, the microphone array 140 is a linear array, a cross array,or a square array. In the linear array, as shown in FIG. 2, themicrophones M are arranged on an axis orthogonal to the direction ofamplifying sound (hereinafter, simply referred to as sound amplificationdirection) which is recognized when sound is amplified by the speakersystem 130. As shown in FIG. 3, the cross array is constructed by afirst array in which a plurality of microphones M are arranged in thesame axial direction as the sound amplification direction and a secondarray in which a plurality of microphones M are arranged in parallel onan axis orthogonal to the first array. In the square array, as shown inFIG. 4, a plurality of microphones M are arranged on the plane parallelwith the floor surface using the center of the listening position as areference.

The microphone array 140 is a circular array or a radial array. In thecircular array, as shown in FIG. 5, a plurality of microphones M arearranged so as to form a circular shape on the plane parallel with thefloor surface using the center of the listening position as a reference.In the radial array, as shown in FIGS. 6 and 7, a plurality ofmicrophones M are arranged in parallel in six or five directions atequal intervals by using the sound amplification direction as areference on the surface parallel with the floor surface.

In the microphone array 140, the result of detection of the directivityin amplified sound in the listening room 10 which will be describedlater varies according to the number of the microphones M and the arrayshape. Generally, the larger the number of the microphones M is, themore the directivity of the amplified sound can be detected strictly. Todetect the directivity of amplified sound from all of the directions tothe listening position, it is desirable to arrange a plurality ofmicrophones M using the center of the listening position as a reference.

The configuration and operation of the signal processing apparatus 120in the embodiment will now be described.

The signal processing apparatus 120 of the embodiment has, as shown inFIG. 1, an input processor 121 to which bit stream data in apredetermined format having channel components is input, and whichconverts the bit stream data to audio data in a signal format used atthe time of decoding to an audio signal of each channel, a signalprocessor 200 for performing a signal process such as decoding of theconverted audio data to an audio signal of each channel and adjustmentof the reproduction characteristic including a reverberationcharacteristic on amplified sound on the channel unit basis, a D/Aconverter 122 for digital-to-analog (hereinafter, referred to as D/A)converting an audio signal of each channel to an analog signal, and apower amplifier 123 for amplifying the reproduction level of the signalof each channel on the channel unit basis.

The signal processing apparatus 120 also has a test signal generator 124for generating a test signal used at the time of analyzing spatialcharacteristics of the listening room 10, particularly, a reverberationcharacteristic in the embodiment, a microphone amplifier 125 foramplifying a signal collected by the microphone array 140 to a presetsignal level, an A/D converter 126 for performing analog-to-digital(A/D) conversion that converts the amplified sound signal as an analogsignal to a digital signal, a spatial characteristic analyzer 127 foranalyzing the spatial characteristics of the listening room 10 on thebasis of the sound-collected signal converted to the digital signal, anoperating unit 128 for operating each of the components; and a systemcontroller 129 for controlling each of the components on the basis ofthe operation of the operating unit 128.

For example, the input processor 121 of the embodiment corresponds to afirst obtaining device of the invention, and the signal processor 200corresponds to an adjusting device. For example, the power amplifier 123of the embodiment corresponds to an output control device of theinvention, and the test signal generator 124 corresponds to a generatingdevice of the invention. Further, for example, the spatialcharacteristic analyzer 127 of the embodiment corresponds to a secondobtaining device and a recognizing device of the invention.

To the input processing unit 121, the bit stream data in a predeterminedformat having channel components is input. The input processing unit 121converts the input bit stream data to audio data in a predeterminedformat, and outputs the converted audio data to the signal processor200.

To the signal processor 200, the audio data output from the inputprocessing unit 121 and the test signal generated by the test signalgenerator 124 is input. The signal processor 200 decodes the input audiodata to audio signals of respective channels, performs a predeterminedsignal process on the channel unit basis to adjust the reproductioncharacteristic, and outputs the audio signal of each channel to thecorresponding D/A converter 122. The signal processor 200 performs apredetermined process for amplifying an input test signal to each of thespeakers under control of the system controller 129, and outputs thetest signal as an audio signal to each of the D/A converter 122 on thechannel unit basis.

Specifically, as described later, the signal processor 200 determines acoefficient necessary at the time of respective performing signalprocesses such as frequency characteristic adjustment, delay timecontrol, signal level control, and reverberation control on an inputsignal on the basis of the data of parameters output from the spatialcharacteristic analyzer 127, performs a signal process on the basis ofrespective determined coefficients, and outputs the resultant torespective D/A converters 122.

The details of the configuration and operation of the signal processor200 in the embodiment will be described later.

To the D/A converters 122, each of the audio signals subjected to eachof the signal processes are input on the channel unit basis. The D/Aconverters 122 convert each of the audio signals and test signals as theinput digital signals to analog signals and output the analog signals tothe respective power amplifiers 123.

To the power amplifiers 123, the processed audio signals are input onthe channel unit basis. Under control of the system controller 129, eachof the power amplifiers 123 amplifies the signal level of the audiosignal of a corresponding channel on the basis of an instruction ofvolume designated by the operating unit 128, and outputs the amplifiedaudio signal to each of the speakers corresponding to each of thechannels.

The test signal generator 124 generates a test signal used at the timeof analyzing the spatial characteristics such as the frequencycharacteristic of the listening room 10, the level characteristic of areproduction level, the delay time analysis, and a reverberationcharacteristic, and outputs the generated test signal to the signalprocessor 200. Specifically, the test signal generator 124 generates atest signal such as sweep signal for sweeping, for example, white noise,pink noise, or frequencies in a predetermined frequency range undercontrol of the system controller 129, and outputs the generated testsignal to the signal processor 200.

The test signal generator 124 of the embodiment generates a test signalinterlockingly with the signal processor 200 and the spatialcharacteristic analyzer 127 under control of the system controller 129,and used at the time of executing processes of adding and generating areverberation component which will be described later.

To the microphone amplifier 125, the collected sound signal which isoutput from each of the microphones M in the microphone array 140 isinput. The microphone amplifier 125 amplifies the input collected soundsignal to a preset signal level and outputs the amplified collectedsound signal to the A/D converter 126.

The collected sound signal which is output from each of the microphonesM output from the microphone amplifier 125 is input to the A/D converter126. The A/D converter 126 converts the input collected sound signal asan analog signal to a digital signal, and outputs the collected soundsignal converted to the digital signal to the spatial characteristicanalyzer 127.

To the spatial characteristic analyzer 127, the collected sound signalconverted to the digital signal is input. On the basis of the inputcollected sound signal, the spatial characteristic analyzer 127 analyzesthe frequency characteristic of the output amplified sound on thechannel unit basis, the reproduction level of the sound, delay time, andthe reverberation characteristic of the sound. The spatialcharacteristic analyzer 127 calculates a predetermined parameter fordetermining a coefficient necessary at the time of performing signalprocesses in the signal processor 200 on the basis of analysis results,and outputs the calculated parameter data to the signal processor 200.In particular, the spatial characteristic analyzer 127 of the embodimentperforms the analyses on the basis of the sound-collected signal basedon the test signal output from the speaker system 130 and calculateseach parameter.

The details of the configuration and operation of the spatialcharacteristic analyzer 127 in the embodiment will be described later.

The operating unit 128 is constructed by a remote controller including anumber of keys such as various confirmation buttons, selection buttons,and numeral keys, or various key buttons. The operating unit 128 is usedto enter an instruction for analysis of the spatial characteristic inthe listening room 10. In particular, in the embodiment, the operatingunit 128 is used to perform operation related to processes of generatingand adding a reverberation component to an audio signal to be amplified.

The system controller 129 controls, in a centralized manner, the generalfunctions for amplifying the audio signals from the speakers. Inparticular, the system controller 129 makes a predetermined process on asound signal collected by each of the microphones M, and has adirectional characteristic indicative of the arrival direction of areverberation component in the amplified sound at the listeningposition. The system controller 129 performs a control of an analysisprocess of analyzing the reverberation characteristic indicative ofattenuation with time in the sound field space, of strength of theamplified sound in the listening position (hereinafter, referred to asreverberation characteristic analyzing process). The system controller129 also performs a control of a process of calculating a coefficientnecessary at the time of performing a reverberation control(hereinafter, referred to as reverberation control coefficient) in thesignal processor 200 on the basis of the analyzed reverberationcharacteristic of the listening room 10 and a process of setting thecoefficient (hereinafter, the calculating process and the settingprocess will be referred to as a reverberation control coefficientsetting process).

The reverberation characteristic denotes a characteristic showingattenuation with time of the amplitude level (strength) of an amplifiedsound which is listened in an arbitrary listening position in thelistening room 10. Specifically, the reverberation characteristicdenotes a characteristic of an amplitude level attenuation ratio using,as reference, first arrived amplified sound (direct sound) in thelistening position from an arbitrary speaker and the time in each offrequency bands on the basis of the sound-collected signal in an inputtest signal.

The details of the operations of the reverberation characteristicanalyzing process and the reverberation control coefficient settingprocess of the system controller 129 in the embodiment will be describedlater.

Referring now to FIG. 8, the configuration and operation of the signalprocessor 200 of the embodiment will now be described. FIG. 8 is a blockdiagram showing the configuration of the signal processor 200 in theembodiment.

As described above, the signal processor 200 decodes input audio data toan audio signal of each channel, and switches entry between the decodedaudio signal of each channel and a test signal output from the testsignal generator 124. The signal processor 200 performs a predeterminedsignal process on the channel unit basis on an input signal, therebyadjusting the reproduction characteristic, and performs a predeterminedprocess for amplifying an input test signal on the speaker unit basisunder control of the system controller 129.

Specifically, the signal processor 200 has: a decoder 210 for decodinginput audio data to audio signals in channels; an input switching unit220 for switching between the audio signals in each of the channelsobtained from the data and an input test signal; a frequencycharacteristic adjusting circuit 230 for adjusting the frequencycharacteristics of the audio signals in each of the channels or the testsignal; a signal level/delay adjusting unit 240 for adjusting the signallevel between the channel of a signal and the other channels anddelaying a signal input on the channel unit basis; a reverberationcontrol circuit 250 for generating a reverberation component of an audiosignal of each channel or the test signal on the basis of areverberation control coefficient which is set as will be describedlater and adding the reverberation component to the audio signal or thetest signal; and a signal process controller 260 for controlling each ofthe components of the signal processor 200 under control of the systemcontroller 129.

The signal processor 200 has the frequency characteristic adjustingcircuit 230, the signal level/delay adjusting unit 240, and thereverberation control circuit 250 for each of the channels, and thesignal process controller 260 and the other components are connected toeach other via a bus B.

Audio data is input to the decoder 210. The decoder 210 decodes theinput audio data to audio signals of respective channels, and outputsthe audio signals to the input switching unit 220 on the channel unitbasis.

To the input switching unit 220, the audio signals decoded on thechannel unit basis and a test signal output from the test signalgenerator 124 are input. The input switching unit 220 switches betweenthe audio signal output from the decoder 210 and the test signalgenerated by the test signal generator 124 under control of the signalprocess controller 260, and outputs the switched signal to the frequencycharacteristic adjusting circuits 230. At the time of outputting a testsignal, the input switching unit 220 outputs the test signal to thechannels or one of the channels selected by the signal processcontroller 260.

In each of the frequency characteristic adjusting circuits 230, a filterfactor for adjusting the gain of a signal component is set on thefrequency band unit basis under control of the signal process controller260. To each of the frequency characteristic adjusting circuit 230, aninput audio signal of each channel or a test signal is input. Thefrequency characteristic adjusting circuit 230 adjusts the frequencycharacteristic on the input signal on the basis of the set filterfactor, and outputs the adjusted frequency characteristic to thecorresponding signal level/delay adjusting unit 240.

In each of the signal level/delay adjusting units 240, under control ofthe signal process controller 260, a coefficient for adjusting theattenuation ratio in each of the channels (hereinafter, referred to asan attenuation coefficient) in each channel and a coefficient foradjusting a delay amount (delay time) in the audio signal correspondingto the channel or the test signal (hereinafter, referred to as delaycontrol coefficient) are set. To each of the signal level/delayadjusting units 240, the audio signal whose frequency characteristic isadjusted in each of the frequency bands or the test signal is input.Each of the signal level/delay adjusting units 240 adjusts theattenuation ratio and the delay amount of each of the channels in theinput signal on the basis of the set attenuation coefficient and thedelay control coefficient, and outputs the audio signal or test signalin which the attenuation ratio and the delay amount are adjusted to thecorresponding reverberation control circuit 250.

In each of the reverberation control circuit 250, a reverberationcontrol coefficient determined by the signal process controller 260 aswill be described later is set. The reverberation control circuits 250executes a reverberation control on the audio signal or test signalsubjected to the signal level adjustment, and outputs the resultantsignal to each of the D/A converters 122.

Specifically, to the reverberation control circuits 250, the audiosignal or test signal whose signal level and delay amount are adjustedare input. The reverberation control circuits 250 divides the audiosignals or test signals input on the channel unit basis to a pluralityof frequency bands. Each of the reverberation control circuits 250performs the reverberation control by generating the reverberationcomponents in each of the frequency bands in the input audio signal ortest signal input on the basis of the reverberation control coefficientwhich will be described later, and adding the generated reverberationcomponent to the input audio signal or test signal, and outputs thesignal subjected to the reverberation control to each of the D/Aconverters 122.

At the time of performing a reverberation control by generating areverberant component for an input signal and adding it, thereverberation control circuit 250 performs the reverberation controlincluding the direction characteristic of the reverberation component,thereby adjusting a reverberation component to be generated among thechannels. That is, the reverberation control circuit 250 of theembodiment performs the reverberation control on the speaker unit basis(hereinafter, also referred to as a speaker system) on an input signalof each channel so that the reverberation component has the directioncharacteristic when the reverberation component is amplified.

The details of the configuration and operation of the reverberationcontrol circuit 250 in the embodiment will be described later. Forexample, the reverberation control circuit 250 of the embodimentcorresponds to an adjusting device of the invention.

In response to an instruction of the system controller 129, the signalprocess controller 260 determines and sets coefficients of each of thefrequency characteristic adjusting circuits 230, each of the signallevel/delay adjusting units 240, and each of the reverberation controlcircuits 250.

Specifically, the signal process controller 260 calculates the filterfactor, attenuation coefficient, and delay control coefficient on thebasis of the data of the parameters analyzed by the spatialcharacteristic analyzer 127 and sets them in the components. Inaddition, the signal process controller 260 calculates a reverberationcontrol coefficient for performing a control of generating areverberation component in the reverberation control circuit 250 on thebasis of the reverberation parameters, and sets the calculatedreverberation control coefficient in the reverberation control circuit250.

In particular, the signal process controller 260 in the embodiment has atable for calculating reverberation control coefficients in thereverberation control circuit 250 on the basis of the inputreverberation parameters. When the reverberation parameter is input, thesignal process controller 260 calculates a predetermined reverberationcontrol coefficient on the basis of the table.

For example, to the signal process controller 260, as will be describedlater, a reverberation parameter for calculating a coefficient used atthe time of controlling a reverberation component having the directioncharacteristic is input. On the basis of the reverberation parameterindicative of the characteristic of the reverberation component analyzedas will be described later, the signal process controller 260 adds thelevel of the reverberation component and delay time to the audio signalof each channel or the test signal, and calculates the reverberationcontrol coefficient for adjustment among channels of the reverberationcomponent to be added so that the added reverberation component can belistened from the analyzed arrival direction. The signal processcontroller 260 sets the calculated reverberation control coefficient inthe reverberation control circuit 250.

In the embodiment, the signal process controller 260 calculates areverberation control coefficient in each channel, in each of the presetfrequency bands, and in each of the speaker systems as will be describedlater.

The configuration and operation of the spatial characteristic analyzer127 in the embodiment will be described with reference to FIGS. 9 and10. FIG. 9 is a block diagram showing the configuration of the spatialcharacteristic analyzer 127 in the embodiment. FIG. 10 is a diagram forexplaining the reverberation characteristic analysis in the embodiment.

To the spatial characteristic analyzer 127, a sound-collected signalgenerated by collecting a sound amplified on the basis of a test signalis input. As described above, on the basis of the input sound-collectedsignal, the spatial characteristic analyzer 127 performs analysis of thefrequency characteristic of the amplified sound output on the channelunit basis, analysis of the sound pressure level of the amplified sound,delay time analysis, and analysis of the reverberation component of theamplified sound. On the basis of results of the analysis, the spatialcharacteristic analyzer 127 outputs data to the signal processor 200 viathe system controller 129.

The spatial characteristic analyzer 127 includes: a frequencycharacteristic analyzer 127A for analyzing the frequency characteristicof the listening room 10; a sound pressure level/delay time analyzer127B for analyzing the sound pressure level and delay time of amplifiedsound from each of the speakers in the listening room 10; and thereverberation characteristic analyzer 127C for analyzing thereverberation characteristic of the listening room 10 and calculatingthe reverberation parameter when the reverberation control coefficientsetting process is executed.

The frequency characteristic analyzer 127A analyzes the frequencycharacteristic in the install position (listening position) of themicrophone array 140 in the listening room 10 on the basis of thesound-collected signal in an input test signal, and outputs the resultof analysis as data of a predetermined parameter to the signal processcontroller 260 via the system controller 129. The sound pressurelevel/delay time analyzer 127B analyzes the sound pressure level and thedelay time of amplified sound from each of the speakers in the installposition of the microphone array 140 in the listening room 10 on thebasis of the collected-sound signal in an input test signal. The soundpressure level/delay time analyzer 127B outputs the analysis result asdata of the predetermined parameter to the signal process controller 260via the system controller 129.

The reverberation characteristic analyzer 127C analyzes thereverberation characteristic including the direction characteristic ofthe reverberation component of the amplified sound at the listeningposition in the listening room 10 on the basis of change with time ofthe reverberation component of a collected test signal at the time ofanalyzing the reverberation characteristic of the listening room 10, andoutputs the analysis result as data of a predetermined reverberationparameter to the signal process controller 260 via the system controller129.

More specifically, the reverberation characteristic analyzer 127C of theembodiment calculates the ratio of the amplitude level which attenuateswith time of the reverberation component with respect to that of adirect component which directly arrives at the listening position on thesound-collected signals collected by the microphones M of the microphonearray 140. At the time of calculating the amplitude level ratio of thereverberation component, the reverberation characteristic analyzer 127Ccalculates the preset distance between one microphone M and anothermicrophone M in the microphone array 140, that is, the reverberationcharacteristic at each of predetermined angles in the listening positionon the basis of the distance between the microphones M in the microphonearray 140.

Usually, at the listening position, in the case of using a linear arrayin which the microphones M of the microphone array 140 are arranged onthe plane parallel with the floor surface of the listening room 10 in adirection perpendicular to the front surface of the listening room 10,that is, the radial axis of the center speaker 131, when amplified soundis reflected by a wall surface or the like of the listening room and thereflected amplified sound reaches the listening position from apredetermined direction, amplified sound (hereinafter, referred to asreverberation component) having a predetermined delay from amplifiedsound (hereinafter, referred to as direct component (direct sound))directly reached the listening position from the speaker system 130, andhaving a predetermine angle (θ) with respect to the front surface iscollected by the microphone M. Therefore, in the amplified soundreflected by the wall surface of the listening room 10, which isrecognized by the microphone M, an amplitude difference of the reachtime and the sound pressure level occurs on the basis of the arrivaldirection in the microphone M as a reverberation component.

For example, as shown in FIG. 10, when the amplified sound entering froma direction A having a predetermined angle (θ) from the radial axis ofthe center speaker 131 and reflected by the wall surface arrives as areverberation component at the microphone array 140, an arrival timedifference (dt) occurs with respect to the direct component, and apredetermined phase difference occurs in each of the frequenciesincluded in the amplified sound due to the arrival time difference.

In the embodiment, the reverberation characteristic analyzer 127C cananalyze the reverberation characteristic including the directioncharacteristic of the amplified sound in the listening position byperforming a predetermined delay process on a plurality ofsound-collected signals in the microphones M and adding thesound-collected signals subjected to the delay process.

Specifically, in the embodiment, when a reverberation component includedin amplified sound has a predetermined angle with respect to the radialaxis of the center speaker 131 as a reference in the listening position,in the reverberation component, the arrival time difference (dt) fromthe arrival time of the direct component which directly arrived from thecenter speaker 131 and the phase difference due to the arrival timedifference occur. Therefore, the reverberation characteristic analyzer127C of the invention performs the delay process using a delay amountexpected on the basis of the arrival direction in which each of thesound-collected signals is to be analyzed, adds the sound-collectedsignals subjected to the delay process and, on the basis of the resultof the addition, recognizes the reverberation characteristic in each ofthe arrival directions in which a sound-collected signal is to beanalyzed. As a result, by performing the process in all of the arrivaldirections in which the sound-collected signals are to be analyzed, thereverberation characteristic analyzer 127C can analyze the reverberationcharacteristic including the direction characteristic of amplified soundincluding the reverberation component.

Specifically, in the embodiment, the distance from the speaker system130 to the listening position, for example, the distance from the centerspeaker 131 to the center of the microphone array 140 is preset. Thereverberation characteristic analyzer 127C calculates delay time in eachof the sound-collected signals on the basis of the arrangement positionsof the microphones M by using the center of the listening position as areference, that is, the center microphone M as a reference in each ofthe angles of the preset arrival directions, delays the sound-collectedsignals, and adds the delayed sound-collected signals in each of theangles of the preset arrival directions, thereby analyzing thereverberation characteristic in each of the arrival directions withrespect to the listening position.

For example, in the embodiment, the arrival direction in which theanalysis is to be made is preset every 30 degrees using the radial axisof the center speaker 131 as a reference. On the basis of thearrangement position of each of the microphones M in the microphonearray 140, the reverberation characteristic analyzer 127C calculates adelay amount in each of the arrival directions in which the analysis isto be made and stores the delay amount on the inside. The reverberationcharacteristic analyzer 127C puts the preliminarily calculated delay oneach of sound-collected signals collected by the microphones M in eachof the predetermined arrival directions and adds the sound-collectedsignals, thereby calculating a piece of data (hereinafter, referred toas measurement data) every predetermined arrival direction. On the basisof the measurement data in each of the predetermined arrival directions,the reverberation characteristic analyzer 127C calculates thereverberation characteristic every predetermined arrival direction, forexample, reverberation time indicative of time in which the amplitudelevel drops to −60 dB when the direct component is used as a reference,the energy distribution of each reverberation component, the timecharacteristic of energy of each of the reverberation components, andthe like.

The spatial characteristic analyzer 127 of the embodiment presetspredetermined weights in correspondence with the arrangement of themicrophones M. On the basis of sound-collected signals collected by themicrophones M, the spatial characteristic analyzer 127 adds thesound-collected signals collected by the microphone array 140 on thebasis of the set weights. For example, by decreasing the weight on thesound-collected signals collected by the microphones M arranged, withdistance from the center of the listening position, further, the arrivaldirection of the reverberation component can be recognized accurately.Consequently, the reverberation characteristic including the arrivaldirections of the reverberation components can be analyzed accurately.

The reverberation characteristic analyzer 127C compares thereverberation characteristic including the arrival direction of thereverberation component with a desired reverberation characteristic, forexample, a reverberation characteristic which is set via the operatingunit 128. As a result, each of the signal process controllers 260calculates a reverberation parameter for calculating a coefficient whichis used when the reverberation component is to be added in thereverberation control circuit 250.

Specifically, the reverberation characteristic analyzer 127C calculatesa reverberation parameter for calculating a reverberation controlcoefficient necessary when the reverberation component is controlled inthe reverberation control circuit 250 in the signal process controller260. The reverberation characteristic analyzer 127C calculates areverberation parameter including a parameter for generating areverberation component indicative of the direction characteristic.

Next, the configuration and operation of the reverberation controlcircuit 250 in the embodiment will be described with reference to FIG.11. FIG. 11 is a block diagram showing the configuration of thereverberation control circuit 250 in the signal processor 200 in theembodiment.

To the reverberation control circuit 250, the audio signal of eachchannel or test signal subjected to the signal level adjustment isinput. When the audio signal or test signal is input, the reverberationcontrol circuit 250 divides the input audio signal or test signal intosignals of the same number as the number of speakers in the speakersystem 130. On the basis of the reverberation control coefficient whichis set by the signal process controller 260, the reverberation controlcircuit 250 performs reverberation component adjustment of generatingand adding a reverberation component on each of the divided signals ofthe audio signal or test signal (hereinafter, referred to as dividedsignal), adds the resultant signals on the channel unit basis, that is,on the output channel basis of each speaker, and outputs the addedsignal of each channel to the corresponding D/A converter 122.

Specifically, the reverberation control circuit 250 has, as shown inFIG. 11, a signal divider 251, a signal component generator 252, and asignal component combining unit 253. The signal divider 251 divides theinput audio signal or test signal by the same number as that of thespeakers of the speaker system 130. When the reverberation controlcoefficient is set by the signal process controller 260 and the audiosignal or test signal is input, the signal component generator 252generates a reverberation component every divided signal on the basis ofthe set reverberation control coefficient and adds the generatedreverberation component to the input original divided signal. The signalcomponent combining unit 253 combines the divided signals to which thereverberation components are added for each of the speaker systems.

The signal component generator 252 adds the reverberation componentevery preset frequency band, and the reverberation control coefficientwhich is set in the signal component generator 252 is set every channel,every frequency band, and every speaker system as described above.

The signal divider 251 is provided for each channel. To the signaldivider 252, the audio signal or test signal output from the signallevel adjuster 240 is input on the channel unit basis. When the audiosignal or test signal is input, the signal divider 251 divides the inputaudio signal or test signal of each channel into a plurality of signalshaving the same component and of the same number as that of the speakerson the channel unit basis, and outputs the divided signals to the signalcomponent generators 252.

For example, in the embodiment, the signal divider 251 divides the inputaudio signal or test signal of each channel by “6” which is the numberof the speaker systems, and outputs the divided signals to the signalcomponent generators 252. That is, the signal divider 251 of theembodiment outputs the divided signals to the signal componentgenerators 252 for the channels and for the speaker systems.

The signal component generators 252 are provided for the respectivechannels and for the respective speaker systems. In each of the signalcomponent generators 252, the reverberation control coefficientcalculated as described above is set for each channel and for eachspeaker system by the signal process controller 260. To the signalcomponent generators 252, a plurality of divided signals are input onthe channel unit basis. When the corresponding divided signal is input,the signal component generator 252 generates a reverberation component,adds the reverberation component to the input divided signal, andoutputs the resultant signal to the signal component combining unit 253in the corresponding speaker system.

Specifically, in the signal component generator 252, a reverberationcontrol coefficient is preliminarily set for each channel, eachfrequency band, and each speaker system by the signal process controller260. The signal component generator 252 performs a delay process on theinput divided signal on the basis of the reverberation controlcoefficient.

For example, in the embodiment, each of the signal component generators252 performs a filter process using an FIR (Finite Impulse Response)filter every frequency band and every speaker system. On the basis ofthe reverberation control coefficient, that is, the filter coefficientset by the signal process controller 260, at the time of amplifyinginput divided signals to the speakers, a reverberation component isgenerated and added so that the reverberation time becomes desiredreverberation time in the listening room 10.

The signal component combining units 253 are provided for the speakersystems. To each of the signal component combining units 253, theplurality of divided signals to which the reverberation componentoutputs from the corresponding signal component generators 252 are addedare input. Each of the signal component combining units 253 adds theinput divided signals for the corresponding speaker system, therebygenerating a signal for each speaker system (hereinafter, referred to asa speaker signal). The signal component combining unit 253 outputs thegenerated speaker signal to the corresponding D/A converter 122.

Next, the operations in the reverberation characteristic analyzingprocess of the embodiment and the reverberation control coefficientsetting process based on the reverberation characteristic analyzingprocess will be described with reference to FIG. 12. FIG. 12 is aflowchart showing operations of the reverberation characteristicanalyzing process of the embodiment and the reverberation controlcoefficient setting process based on the reverberation characteristicanalyzing process.

First, when the system controller 129 detects an instruction to startthe reverberation characteristic analyzing process and the reverberationcontrol coefficient setting process from the user via the operating unit128 (step S11), the system controller 129 selects one speaker whosereverberation characteristic has not been analyzed and in which thereverberation control coefficient has not been set (step S12).

After that, the system controller 129 makes the test signal generator124 generate a predetermined test signal and output the test signal fromthe selected speaker (step S13). Specifically, the system controller 129controls the signal process control to stop outputting the signal levelin the power amplifier 123 or stop outputting of the other speakerswhich are not selected such as inhibition of an input in the signalprocessor 200, and start outputting the test signal from the selectedspeaker.

Subsequently, the system controller 129 makes the test signal outputfrom the selected speaker and the amplified sound from the speakers arecollected by the microphone array 140. The system controller 129 makesthe spatial characteristic analyzer 127 obtain the collected amplifiedsound as sound-collected signals via the microphone amplifier 125 andthe A/D converter 126 (step S14).

The spatial characteristic analyzer 127 temporarily internally storesthe obtained sound-collected signals. It is sufficient for the systemcontroller 129 to make the spatial characteristic analyzer 127 obtaineach sound-collected signal once. Alternatively, to improve the S/Nratio, the system controller 129 may repeat the operation a plurality oftimes to thereby obtain a plurality of sound-collected signals. In thiscase, prior to a reverberation characteristic analysis which will bedescribed later, the spatial characteristic analyzer 127 averages theobtained sound-collected signals for each of the microphones M, therebycalculating a sound-collected signal as the base of the analysis.

Subsequently, the system controller 129 selects one preset arrivaldirection angle which has not been selected yet, and executes thefollowing process (step S15). In the embodiment, as described above, thesystem controller 129 executes the following process every 30 degrees byusing the radial axis of the center speaker 131 as a reference.

First, the system controller 129 makes the spatial characteristicanalyzer 127 perform a delay process of delaying a sound-collectedsignal collected by each of the microphones M in the microphone array140 on the basis of a delay amount in the selected arrival directionangle, and adds the sound-collected signals subjected to the delayprocess to calculate one measurement data (step S16).

Specifically, as described above, the spatial characteristic analyzer127 reads out the delay amount corresponding to the microphone M whichis internally calculated in advance on the inside, performs a delayprocess on the collected signal on the basis of the read delay amount,and adds sound-collected signals subjected to the delay process.

Subsequently, the system controller 129 calculates the reverberationcharacteristic in the arrival direction on the basis of measurement datacalculated by the spatial characteristic analyzer 127 (step S17) and, onthe basis of the calculated reverberation characteristic, calculates thereverberation parameter (step S18).

Specifically, the spatial characteristic analyzer 127 of the embodimentcalculates the time characteristic of the energy of the reverberationcomponent on the basis of the calculated measurement data, andcalculates the calculated time characteristic of the energy as thereverberation parameter in the arrival direction.

Subsequently, the system controller 129 determines whether or not thereis an unselected arrival direction angle in which the reverberationparameter is to be calculated (step S19). In the case where there is anunselected arrival direction angle in which the reverberation parameteris to be calculated, the system controller 129 returns to the process ofstep S15. In the case where there is no unselected arrival direction inwhich the reverberation parameter is to be calculated, the systemcontroller 129 determines whether or not there is a speaker in which theanalysis of the reverberation characteristic and setting of thereverberation parameter has not been performed yet (step S20).

In the case where the system controller 129 determines there is aspeaker in which the analysis of the reverberation characteristic andsetting of the reverberation parameter has not been performed yet, thesystem controller 129 returns to the process of step S12.

On the other hand, in the case where the system controller 129determines that the analysis of the reverberation characteristic and thecalculation of the reverberation control parameter has been finished inall of the speakers, the system controller 129 makes the spatialcharacteristic analyzer 127 output the calculated reverberationparameters to the signal process controller 260, and makes the signalprocess controller 260 calculate reverberation control coefficients onthe basis of the reverberation parameters (step S21).

Finally, the system controller 129 makes the signal process controller260 set the calculated reverberation control coefficients in thereverberation control circuit 250 (step S22) and finishes the operation.

After that, when sound source is reproduced from the sound source outputapparatus 110 and an audio signal is input to the signal processingapparatus 120, in the reverberation addition component generator, thesignal process is performed on the audio signal on the basis of thereverberation control coefficient which is set as described above.Specifically, the reverberation characteristic of the audio signal isadjusted, and the audio signal subjected to the signal process isamplified and output from the speaker system 130.

As described above, according to the embodiment, the surround system 100of the embodiment has: the speaker system 130 installed in the listeningroom 10 and constructed by the plurality of speakers; the signalprocessing apparatus 120 for recognizing a reverberation characteristicof the listening room 10 by outputting the audio signal from the speakersystem 130 and, on the basis of the recognized reverberationcharacteristic, adjusting a reverberation component in the audio signaloutput from the speaker system 130; and the microphone array 140constructed by the plurality of microphones M disposed in the listeningroom 10 and having the same characteristics, in which the distancesamong the microphones M are preliminarily determined and, when an audiosignal is output from the speaker system 130 to the listening room 10,for collecting the amplified sound in a specific listening position inthe listening room 10. The signal processing apparatus 120 has: theinput processor 121 for obtaining a sound signal as an audio signal; thetest signal generator 124 for generating, as an audio signal, a testsignal used for analyzing a reverberation characteristic of thelistening room 10; the power amplifier 123 for amplifying at least oneof the sound signal and the test signal and outputting the amplifiedsignal from the speaker system 130; the spatial characteristic analyzer127 for obtaining, as an amplified sound signal, the amplified soundcollected by the microphone array 140 and, on the basis of the obtainedamplified sound signal, recognizing a reverberation characteristichaving the direction characteristic indicative of the arrival directionof a reverberation component of the amplified sound in the listeningposition and indicative of attenuation with time in the listening room10 on the intensity of sound in the listening position of the amplifiedsound; and the reverberation control circuit 250 for adjusting thereverberation characteristic of the audio signal to be amplified andoutput from an obtained speaker on the basis of the recognizedreverberation characteristic.

With the configuration, the surround system 100 of the embodimentobtains, as the amplified sound signal, the amplified sound collected bythe microphone array 140 constructed by the plurality of microphones Mhaving the same characteristic and in which the distances among themicrophones M are preliminarily determined and, on the basis of theobtained amplified sound signal, recognizes a reverberationcharacteristic having the direction characteristic indicative of thearrival direction of a reverberation component of the amplified sound inthe listening position in the listening room 10 and indicative ofattenuation with time in the listening room 10 on the intensity of soundin the listening position of the amplified sound. The surround system100 of the embodiment adjusts the reverberation characteristic of soundsource to be amplified and output from the obtained speaker on the basisof the recognized reverberation characteristic.

Therefore, at the time of recognizing the reverberation characteristicof each amplified sound, the surround system 100 of the embodiment canalso recognize the arrival direction of the reverberation component.Consequently, the reverberation characteristic at the time of amplifyingsound source from a CD, DVD, or the like and outputting the amplifiedsound from the speaker system 130 can be adjusted on the basis ofreverberation characteristic in the listening room 10 including thearrival direction of the reverberation component. As a result, thesurround system 100 can provide a sound field which is more natural andhaving higher realistic sensation on the basis of the analyzedreverberation characteristic.

In addition, in the surround system 100 of the embodiment, the spatialcharacteristic analyzer 127 recognizes a reverberation characteristichaving a direction characteristic of a reverberation component on thebasis of a phase difference in sound-collected signals collected by themicrophone array 140, on the basis of the sound-collected signalscollected by the microphones M.

Therefore, the surround system 100 of the embodiment can estimate thearrival direction of the reverberation component accurately. At the timeof analyzing a reverberation characteristic on reproduction of soundsource, the surround system 100 can accurately analyze the reverberationcharacteristic including the arrival direction of the reverberationcomponent, and can provide a sound field which is more natural and hashigher realistic sensation on the basis of the analyzed reverberationcharacteristic.

In the surround system 100 of the embodiment, the spatial characteristicanalyzer 127 pre-sets predetermined weights in correspondence with thearrangement of the microphones M, and recognizes a reverberationcharacteristic having a direction characteristic of a reverberationcomponent on the basis of the phase differences among sound-collectedsignals collected by the microphones M and the set weights.

With the configuration, the surround system 100 of the embodiment canmore accurately recognize the arrival direction of the reverberationcomponent by decreasing the weight on the sound-collected signalcollected by the disposed microphones M with distance from the center ofthe listening position. Thus, the reverberation characteristic includingthe arrival direction of the reverberation component can be analyzedaccurately.

In the surround system 100 of the embodiment, the microphone array 140is constructed by the plurality of microphones M arranged on the surfaceparallel with the floor surface of the listening room 10. The surroundsystem 100 of the embodiment is constructed by the first array in whichthe plurality of microphones M are arranged in the same direction as theamplification direction of amplified sound recognized when amplifiedsound is output from the plurality of speakers to the listening room 10,and the second array in which the plurality of microphones Mare arrangedin parallel on the surface orthogonal to the surface on which the firstarray is disposed. In the surround system 100 of the embodiment, themicrophone array 140 has a polygonal shape in which the plurality ofmicrophones are arranged on the surface parallel with the floor surfaceof the listening room 10 by using the center of the listening positionas a reference. In the embodiment, the microphone array 140 isconstructed as described above, so that the arrival direction of thereverberation component can be estimated accurately.

In the foregoing embodiment, the process of setting the reverberationtime by using the 5.1 ch surround system 100 is described. Obviously,the invention can be also applied to other sound reproducing apparatusessuch as a multi-channel system having 7.1 ch or more channels or astereo sound reproducing apparatus like an AV amplifier.

In the embodiment, the signal processing apparatus 120 performs thereverberation control and the other signal processes on the basis of adigital signal output from the sound source output apparatus 110.Obviously, the signal processing apparatus 120 can perform the signalprocesses on the basis of an analog signal output from the sound sourceoutput apparatus 110 or an analog signal input from the outside.

In the embodiment, the microphone array 140 is constructed by themicrophones M having the same characteristic. The microphone array maybe constructed by directional microphones having directivity in apredetermined direction with respect to the microphones. Asound-collected signal may be corrected every predetermined angle bychanging the direction of one directional microphone.

In this case, the reverberation characteristic analyzer 127C calculatesa reverberation parameter using, as measurement data, a sound-collectedsignal as it is without being subjected to the delay process and theadding process. Therefore, in this case as well, at the time ofrecognizing a reverberation characteristic of amplified sound, thearrival direction of the reverberation component can be also recognized.Thus, a sound field which is more natural and having higher realisticsensation can be provided on the basis of the analyzed reverberationcharacteristic.

In the microphone array 140 of the embodiment, the plurality ofmicrophones M are arranged on the surface parallel with the floorsurface of the listening room 10. Obviously, it is also possible todispose a plurality of microphones M on the parallel surface and disposea plurality of microphones also on the surface orthogonal to the floorsurface of the listening room 10, thereby three-dimensionally analyzingthe reverberation characteristic of amplified sound including thereverberation component of the listening room 10.

In the embodiment, the spatial characteristic analyzer 1270 analyzes thereverberation characteristic of the two-dimensional plane in thelistening room 10, that is, the characteristic of the two-dimensionalreverberation component in the same plane as the floor surface of thelistening room 10. Obviously, the reverberation characteristic of thelistening room 10 may be also three-dimensionally analyzed by disposingthe microphone array 140 three-dimensionally to form, for example, arectangular parallelepiped array in place of the square array.

In this case, the signal process controller 260 calculates areverberation control coefficient for three-dimensionally generating thereverberation components and sets the calculated reverberation controlcoefficient in the reverberation control circuits 250.

1-9. (canceled)
 10. A sound reproducing system comprising: a speakersystem constructed by a plurality of speakers disposed in a sound fieldspace; a reverberation adjusting apparatus for recognizing areverberation characteristic in the sound field space by amplifyingsound source by the speaker system and, on the basis of the recognizedreverberation characteristic, adjusting a reverberation component in thesound source which is output from the speaker system; and a microphonearray which is constructed by a plurality of microphones disposed in thesound field space and having the same characteristics, in whichdistances among the microphones are preliminarily determined and, whenthe sound source is amplified and the amplified sound is output from thespeaker system to the sound field space, for collecting the amplifiedsound in a specific listening position in the sound field space, whereinthe reverberation adjusting apparatus comprises: a first obtainingdevice which obtains a sound signal as the sound source; a generatingdevice which generates, as the sound source, a test signal used foranalyzing a reverberation characteristic of the sound field space; anoutput control device which amplifies at least one of the sound signaland the test signal and outputting the amplified signal from the speakersystem; a second obtaining device which obtains, as an amplified soundsignal, an amplified sound collected by the microphone array; arecognizing device which recognizes a reverberation characteristichaving a direction characteristic indicative of an arrival direction ofa reverberation component of amplified sound in the listening positionon the basis of the obtained amplified sound signal, and indicative ofattenuation with time in the sound field space on intensity of sound inthe listening position of the amplified sound; and an adjusting devicewhich adjusts the reverberation characteristic of the sound source to beamplified and output from the obtained speaker on the basis of therecognized reverberation characteristic.
 11. The sound reproducingsystem according to claim 10, wherein the microphone array isconstructed by disposing the plurality of microphones on a surfaceparallel with a floor surface of the sound field space.
 12. The soundreproducing system according to claim 11, wherein the microphone arraycomprises: a first array in which the plurality of microphones arearranged on a surface having the same direction as the amplificationdirection of amplified sound recognized when amplified sound is outputfrom the plurality of speakers to the sound field space; and a secondarray in which the plurality of microphones are arranged in parallel inan axial direction orthogonal to the surface on which the first array isdisposed.
 13. The sound reproducing system according to claim 11,wherein the microphone array has a polygonal shape in which theplurality of microphones are arranged on a surface parallel with a floorsurface of the sound field space using the center of the listeningposition as a reference.
 14. The sound reproducing system according toclaim 10, wherein the recognizing device recognizes a reverberationcharacteristic having a direction characteristic of the reverberationcomponent on the basis of a phase difference in sound-collected signalscollected by the microphone array, on the basis of sound-collectedsignals collected by the microphones.
 15. The sound reproducing systemaccording to claim 13, wherein the recognizing device preliminarily setspredetermined weights in correspondence with arrangement of themicrophones, and recognizes a reverberation characteristic having adirection characteristic of the reverberation component on the basis ofthe phase difference in sound-collected signals collected by themicrophone array and the set weights.
 16. A reverberation adjustingmethod for adjusting a reverberation component in sound source outputfrom a speaker system constructed by a plurality of speakers on thebasis of a reverberation characteristic of a sound field space to whichamplified sound is output from the speaker system, comprising: a testsignal amplifying process for generating a test signal used foranalyzing the reverberation characteristic in the sound field space asthe sound source, and amplifying the generated test signal by thespeaker system; a sound collecting process for collecting, as anamplified sound signal, the test signal output from the speaker systemto the sound field space by a microphone array which is constructed by aplurality of microphones disposed in the sound field space and havingthe same characteristics; a recognizing process for recognizing areverberation characteristic having a direction characteristicindicative of an arrival direction of a reverberation component ofamplified sound in the listening position on the basis of the obtainedamplified sound signal, and indicative of attenuation with time in thesound field space on intensity of sound in the listening position of theamplified sound; and an adjusting process, at the time of obtaining andamplifying sound source to be amplified by the speaker system, foradjusting the reverberation characteristic of the obtained sound signalon the basis of the recognized reverberation characteristic.
 17. Areverberation adjusting apparatus for adjusting a reverberationcomponent in sound source output from a speaker system constructed by aplurality of speakers on the basis of a reverberation characteristic ofa sound field space to which amplified sound is output from the speakersystem, comprising: a first obtaining device for obtaining a soundsignal as the sound source in the case of collecting the sound amplifiedand output to the sound field space by the speaker system in a specificlistening position by a microphone array constructed by a plurality ofmicrophones disposed in the sound field space and having the samecharacteristics; a generating device for generating, as the soundsource, a test signal used for analyzing a reverberation characteristicof the source field space; an output control device for amplifying oneof the sound signal and the test signal and outputting the amplifiedsignal from the speaker system; a second obtaining device for obtainingan amplified sound signal collected by the microphone array; arecognizing device for recognizing a reverberation characteristic havinga direction characteristic indicative of an arrival direction of areverberation component of amplified sound in the listening position onthe basis of the obtained amplified sound signal, and indicative ofattenuation with time in the sound field space on intensity of sound inthe listening position of the amplified sound; and an adjusting devicefor adjusting the reverberation characteristic of the obtained soundsource to be output to the speaker system on the basis of the recognizedreverberation characteristic.
 18. A sound reproducing system comprising:a speaker system constructed by a plurality of speakers disposed in asound field space; a reverberation adjusting apparatus for recognizing areverberation characteristic in the sound field space by amplifyingsound source by the speaker system and, on the basis of the recognizedreverberation characteristic, adjusting a reverberation component in thesound source which is output from the speaker system; and a microphonedisposed in the sound field space, having a direction characteristic ina predetermined direction, when the sound source is amplified and theamplified sound is output from the speaker system to the sound fieldspace, for collecting the amplified sound in a specific listeningposition in the sound field space, wherein the reverberation adjustingapparatus comprises: a first obtaining device which obtains a soundsignal as the sound source; a generating device which generates, as thesound source, a test signal used for analyzing a reverberationcharacteristic of the sound field space; an output control device whichamplifies at least one of the sound signal and the test signal andoutputting the amplified signal from the speaker system; a secondobtaining device which obtains, as an amplified sound signal, anamplified sound collected by the microphone array; a recognizing devicewhich recognizes a reverberation characteristic having a directioncharacteristic indicative of an arrival direction of a reverberationcomponent of amplified sound in the listening position on the basis ofthe obtained amplified sound signal, and indicative of attenuation withtime in the sound field space on intensity of sound in the listeningposition of the amplified sound; and an adjusting device which adjuststhe reverberation characteristic of the sound source to be amplified andoutput from the obtained speaker on the basis of the recognizedreverberation characteristic.